Interactive end-of-chapter exercises

Reliable Data Transfer: RDT 3.0

Consider the RDT 3.0 protocol, for reliably communicating data from a sender to receiver over a channel that can lose or corrupt packets in either direction, and when the maximum delay from sender to receiver and back is not known. The FSMs for the sender and receiver are shown below, with their transitions labeled as SX and RY, respectively.

Now let’s consider the sequence of sender and receiver transitions that would happen when one or more of the following complications occur: a packet (data or ACK) is lost, a timer times out (prematurely or not), or a message is corrupted. One or more of these events has occurred to produce the sequence of transitions below. In the sequence below, one transition has been omitted and replaced with a "*".

Transition Sequence: S0, *, S1, S2, R0, S1, S2, R1, S3, S4, S5, R2, S7, R3, S6, S7, R3, S6, S7, R3, S8

Question List

1. What is the missing transition? To indicate the missing transition, enter S or R, followed by an index.


1. The missing transition is: R3

That's incorrect

That's correct

The answer was: R3

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